This invention relates in general beds and more particularly to a side rail for beds, especially beds and articulated beds of the type that are used in healthcare or home care environments. Most particularly, the invention relates to movable side rails and kinematic motion and locks for movable side rails.
Movable side rails for beds are well known. Conventional side rails are generally supported relative to a bed frame by movable arms. The arms are arranged parallel relative to one another and include opposing ends. One end of each arm is pivotally attached to the bed frame at a fixed pivot point. The other ends of the arms are pivotally attached to opposite ends of the side rail at orbital pivot points. The side rail, bed frame, and arms cooperate to form a parallelogram. As the side rail encounters movement, the arms pivot on the fixed pivot points. The orbital pivot points orbit about the fixed pivot points. When the fixed and orbital pivot points come into linear alignment, the arms tend to bind because of manufacturing tolerances.
What is needed is a side rail that moves without binding or a kinematic motion for a side rail that reduces the risk that the side rail will bind when moved.
The present invention is directed towards a side rail for a convalescent bed that is structured to move without binding. The side rail comprises a main body and a pair of lever arms. A first lever arm has an upper end movably supported relative to the main body by an upper pivot pin and a lower end movably attached to the bed by a lower pivot pin. A second lever arm has an upper end movably supported relative to the main body by an upper pivot pin and a lower end movably attached to the bed by a lower pivot pin. The pivot pins are arranged so that the pivot pins do not come into linear alignment with one another during movement of the lever arms.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.